探討地下水參數化對於臺灣地表水文過程之影響;Effects of the groundwater parameterization on land surface hydrologic processes using WRF-NoahMP in Taiwan.

NCU Institutional Repository > 地球科學學院 > 大氣物理研究所 > 博碩士論文 > Item 987654321/83114

請使用永久網址來引用或連結此文件: http://ir.lib.ncu.edu.tw/handle/987654321/83114

題名:	探討地下水參數化對於臺灣地表水文過程之影響;Effects of the groundwater parameterization on land surface hydrologic processes using WRF-NoahMP in Taiwan.
作者:	陳姿穎;Chen, Tzu-Ying
貢獻者:	大氣科學學系
關鍵詞:	地表水文過程;地下水;土壤濕度;陸氣交互作用;hydrologic processes;groundwater;soil moisture;land-air interaction
日期:	2020-08-24
上傳時間:	2020-09-02 14:56:55 (UTC+8)
出版者:	國立中央大學
摘要:	過去許多研究指出，地表特徵影響陸地–大氣之間的交互作用，如：地形、土地利用形態、植被覆蓋率、土壤質地及土壤溼度等，其中土壤濕度對於陸氣交互作用的影響最為關鍵。土壤中的水分以土壤水或地下水的形式儲存在地表中，且地表水文過程影響土壤水分的分布，進而改變地表能量收支，並影響數值天氣預報的表現，但現今氣象模式中經常使用的地表模式卻過度簡化地表水文的描述，導致模式無法精確的掌握地表特徵，影響近地表天氣特徵的模擬及大氣邊界層的發展，因此本篇研究利用加入地下水參數化方案的地表模式Noah-MP LSM與大氣模式WRF進行耦合模擬，並選擇個案時間為2015年7月30日至2015年8月10日，目的是為瞭解在乾旱事件後到颱風侵襲，大環境乾濕分明的差異，探討加入地下水的處理過程LSM能否更精確的掌握土壤水分的分布及改變陸氣交互作用。為了提供WRF-NoahMP模擬時有良好的地下水位初始場，透過觀測水井資料瞭解臺灣地下水位的分布特性，顯示地下水位變化受到降雨季節分布的影響最顯著，臺灣北部因四季有雨，地下水位淺呈現穩定無明顯年際變化，中部地區則受到5月梅雨季及8月颱風季影響，地下水位呈現雙峰值變化，高值落在6月與9月，而南部地區主要降雨來源為夏季，水位呈單峰值變化。然而因觀測水井皆落在平原地區，並無法得知臺灣山區的地下水位分布，因此利用Noah-MP LSM離線模式並依據地形高度來定義初始地下水位，並運行10個月後得到地下水位與土壤濕度達平衡的初始場，提供WRF-NoahMP進行模擬。離線模式模擬結果顯示可以模擬出與地下水井觀測結果接近的空間分布，但量值上可能還有些差異，因為地下水的變化不只受到降雨影響，還有可能受到人為活動、地質條件等影響，但整體來說，離線模式的模擬結果尚可用來當作WRF模擬所需的初始場資料。然而WRF-NoahMP的模擬更換離線模式初始場後，結果顯示搭配MMF地下水參數化方案的模擬，其地下水位深度模擬的較淺，平原區大多位於土壤層之中，因此會有含水層補充水量到土壤層的機制產生，使土壤濕度增加、潛熱通量增加及近地面溫度降低，且透過地表水文收支的分析，瞭解當地下水的深度低於土壤層下方5公尺時，則不會對陸氣較互作用造成影響。;The land surface hydrologic processes such as surface/subsurface runoff and soil-groundwater interaction strongly affect soil moisture. In order to understand how the land surface hydrologic processes affect the land-air interactions in Taiwan, the WRF model coupled with Noah-MP land surface models were applied and chosen three different runoff options. The difference in the three runoff option in Noah-MP LSM is that a free drainage is specified as the lower boundary condition in option 3 (FD), option 1 (SIMGM) add the groundwater parameterization which considers the water content in aquifer to cacluate the water table depth changing and the option 5 (MMFGW) is more complicated groundwater parameterization which considers the aquifer interact with the soil column and river. Based on observation wells, we can understand the distribution characteristics of Taiwan’s ground-water level. The shallow groundwater level in northern Taiwan is stable and there is no obvious annual change. The groundwater level of central area shows two peak change and the high values in June and September because of the mei-yu at May and typh-oon at August. While the main source of rainfall in the southern region was summer, and the water level showed a single peak change. However, the observation wells are located at plain area, it could not know the groundwater level in mountain area clearly. Therefore, the offline Noah-MP LSM is used to simulate the initial data of groundwater table based on the rough topography criterion and the output is used for WRF simulation. The study period is from 30 July to 10 August 2015 during which a moderate intensity typhoon made a landfall in Taiwan. Before the influence of the typhoon, the atmospheric conditions were relatively dry and calm and soils were also dry. During the dry atmospheric conditions, the SIMGM simulates the less soil moisture in three runoff options because the soil would tranfer the water to aquifer. The MMFGW simulates the most soil moisture because the shallower water table depth in soil column which make aquifer transfer the water to soil column. Therefore, the MMFGW simulates higher latent heat flux and lower 2m temperature. In addition to considering that the groundwater parameterization will affect the meteorological simulation, the depth of the water table would also affect. When the offline model product is replaced as the initial data and compared with the water table provided by the WRF official, there will be a deeper groundwater level in the central and southern plain. This would affect the soil moisture trier and reduce the latent heat flux.
顯示於類別:	[大氣物理研究所 ] 博碩士論文

文件中的檔案:

檔案	描述	大小	格式	瀏覽次數
index.html		0Kb	HTML	199	檢視/開啟

在NCUIR中所有的資料項目都受到原著作權保護.

社群 sharing

資料載入中.....